Men choosing expectant management as primary treatment for prostate cancer

Diagnostic biopsy performed within 4 months of screening visit

Gleason score ≤ 6 in 3 cores or less with no Gleason pattern 4, less than 50% of any core involved in cancer

Clinical stage T1c-T2a (Initial diagnosis of T1a/T1b obtained during a TURP is not allowed)

Serum PSA ≤10 ng/mL

Life expectancy greater than 5 years

Normal kidney and hepatic function as defined by the following criteria:

Total bilirubin less than 1.5 X institutional upper limit of normal (ULN)

AST (SGOT)/ALT(SGPT) less than 1.5 X institutional ULN

Alkaline phosphatase less than 2 X institutional ULN

Creatinine less than 1.4 X institutional ULN

Able to swallow and retain oral medication

No exposure to metformin within 12 months of randomization

No known hypersensitivity or intolerance to metformin hydrochloride

No condition associated with increased risk of metformin hydrochloride-associated lactic acidosis (e.g., congestive heart failure defined as NYHA class III or IV function status, history of acidosis of any type, or habitual intake of ≥ 3 alcoholic beverages per day, or age greater than 80)

Diabetes including type 1 diabetes. Patients with known type 2 diabetes are eligible provided they have not been on metformin during the previous 12 months and are not on any other pharmacological agents.

Concurrent or previous use of anabolic steroids or drugs with anti androgenic properties including 5-ARIs (dutasteride and finasteride)

Other malignancies, with the exception of adequately treated nonmelanoma skin cancer, NMIBC or other solid tumors curatively treated with no evidence of disease for ≥ 5 years

Planned or concurrent participation in other interventional randomized trials including exercise

The presence of any other coexistent medical condition that in the opinion of the investigator would have the potential to significantly limit adherence to medication, or ability to absorb the medication including but not limited to psychiatric conditions, malabsorption syndromes or severe ischemic heart disease

Known hypersensitivity or intolerance to metformin

Concurrent or planned participation in randomized trials of weight loss or exercise interventions or trials targeting insulin, IGF-1 or their receptors, or PI3K inhibitors.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01733836